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8447845f | 1 | #include <stdio.h> |
2 | #include <stdlib.h> | |
3 | #include <sys/types.h> | |
4 | #include <sys/socket.h> | |
5 | #include <netinet/in.h> | |
6 | #include <arpa/inet.h> | |
7 | #include <sys/time.h> | |
8 | #include <time.h> | |
9 | #include <string.h> | |
10 | #include <strings.h> | |
11 | ||
12 | #include "mcast.h" | |
13 | #include "sap.h" | |
14 | ||
15 | #define SAP_ADDR "224.2.127.254" | |
16 | #define SAP_PORT 9875 | |
17 | #define SAP_MAX_SIZE 1024 | |
18 | ||
19 | #define SAP_TIMEOUT 3 | |
20 | ||
21 | #define BUFFSIZE SAP_MAX_SIZE | |
22 | ||
23 | char *get_url_from_sap(char *service) | |
24 | { | |
25 | struct timeval start, curr; | |
26 | struct ip_mreq mreq; | |
27 | unsigned char buffer[BUFFSIZE]; | |
28 | char *url = NULL; | |
29 | int fd; | |
30 | ||
31 | snprintf(buffer,BUFFSIZE,"udp://%s:%u", SAP_ADDR, SAP_PORT); | |
32 | ||
33 | fd = open_mcast(buffer); | |
34 | ||
35 | gettimeofday(&start, NULL); | |
36 | ||
37 | do { | |
38 | int recvd; | |
39 | int sap_version, sap_addrtype, sap_messagetype, sap_encrypted, sap_compressed; | |
40 | in_addr_t sender_address; | |
41 | unsigned char auth_len; | |
42 | unsigned short msgid; | |
43 | unsigned char *payload, *pos, *host = NULL, *proto = NULL, *port = NULL, *sname = NULL; | |
44 | ||
45 | if ((recvd = recv(fd, buffer, BUFFSIZE, 0)) < 1) { | |
46 | perror("recv"); | |
47 | return NULL; | |
48 | } | |
49 | ||
50 | gettimeofday(&curr, NULL); | |
51 | ||
52 | sap_version = (buffer[0] >> 5) & 0x7; | |
53 | sap_addrtype = (buffer[0] >> 4) & 0x1; | |
54 | sap_messagetype = (buffer[0] >> 2) & 0x1; | |
55 | sap_encrypted = (buffer[0] >> 1) & 0x1; | |
56 | sap_compressed = buffer[0] & 0x1; | |
57 | auth_len = buffer[1]; | |
58 | msgid = buffer[2] << 8 | buffer[3]; | |
59 | memcpy(&sender_address, buffer+4, (sap_addrtype?16:4)); | |
60 | payload = buffer + 4 /* (sap_*, auth_len, msgid) */ + (sap_addrtype?16:4) + auth_len; | |
61 | ||
62 | #ifdef DEBUG | |
63 | printf("\n"); | |
64 | printf("SAP-Version: %d\n", sap_version); | |
65 | printf("Adresstyp: %s\n", (sap_addrtype?"IPv6":"IPv4")); | |
66 | printf("Messagetype: %s\n", (sap_messagetype?"Announcement":"Deletion")); | |
67 | printf("Encrypted: %d\n", sap_encrypted); | |
68 | printf("Compressed: %d\n", sap_compressed); | |
69 | printf("Authentication Length: %d\n", auth_len); | |
70 | printf("Sender: %u\n", sender_address); | |
71 | printf("Message Identifier Hash: %u\n", msgid); | |
72 | #endif | |
73 | ||
74 | if (sap_addrtype) | |
75 | continue; /* We don't support IPv6 for now */ | |
76 | ||
77 | #if 0 /* Getstream gets this wrong, see rfc2974 */ | |
78 | if (sap_messagetype) | |
79 | continue; /* We are not interested in deletions */ | |
80 | #endif | |
81 | ||
82 | if (sap_encrypted || sap_compressed) | |
83 | continue; | |
b06a3250 | 84 | |
8447845f | 85 | /* RFC 2327 |
86 | * v=0 | |
87 | * o=- 6dca 1 IN IP4 192.168.100.17:2000 | |
88 | * s=TV Das Erste | |
89 | * t=0 0 | |
90 | * c=IN IP4 192.168.100.17/1 | |
91 | * m=video 2000 http 33 | |
92 | * a=tool:getstream | |
93 | * a=type:broadcast | |
94 | */ | |
95 | ||
96 | pos = payload; | |
97 | while(*pos != 0 && (pos-buffer) < BUFFSIZE) { | |
98 | if (*pos == 0x0d) { | |
99 | *pos = 0; | |
100 | } | |
101 | ||
102 | if (*pos == 0x0a) { | |
103 | *pos = 0; | |
104 | ||
105 | if (!strncasecmp("s=", payload, 2)) { | |
106 | sname = payload + 2; | |
107 | } else if (!strncasecmp("c=", payload, 2)) { | |
108 | int poscnt = 0; | |
109 | ||
110 | payload += 2; | |
111 | while (*payload != 0) { | |
112 | if (poscnt == 2 && *payload == '/') { | |
113 | *payload = 0; | |
114 | break; | |
115 | } | |
116 | ||
117 | if (*payload == ' ') { | |
118 | *payload = 0; | |
119 | poscnt++; | |
120 | ||
121 | /* c=<network type> <address type> <connection address> */ | |
122 | if (poscnt == 2) { | |
123 | host = payload + 1; | |
124 | } | |
125 | ||
126 | if (poscnt > 2) { | |
127 | break; | |
128 | } | |
129 | } | |
130 | payload++; | |
131 | } | |
132 | } else if (!strncasecmp("m=", payload, 2)) { | |
133 | int poscnt = 0; | |
134 | ||
135 | payload += 2; | |
136 | while (*payload != 0) { | |
137 | if (*payload == ' ') { | |
138 | *payload = 0; | |
139 | poscnt++; | |
140 | ||
141 | /* m=<media> <port> <transport> <fmt list> */ | |
142 | if (poscnt == 1) { | |
143 | port = payload + 1; | |
144 | } | |
145 | ||
146 | if (poscnt == 2) { | |
147 | proto = payload + 1; | |
148 | } | |
149 | ||
150 | if (poscnt > 2) { | |
151 | break; | |
152 | } | |
153 | } | |
154 | payload++; | |
155 | } | |
156 | } | |
157 | ||
158 | payload = ++pos; | |
159 | continue; | |
160 | } | |
161 | pos++; | |
162 | } | |
163 | ||
164 | if (sname && proto && port) { | |
165 | if (!host) { | |
166 | struct in_addr inaddr; | |
167 | ||
168 | inaddr.s_addr = sender_address; | |
169 | host = inet_ntoa(inaddr); | |
170 | } | |
171 | ||
172 | #ifdef DEBUG | |
173 | printf("%s -> %s://%s:%s\n", sname, proto, host, port); | |
174 | #endif | |
175 | ||
176 | if (strlen(service) < strlen(sname)) { | |
177 | sname += strlen(sname) - strlen(service); | |
178 | } | |
179 | ||
180 | if (!strncasecmp(service, sname, strlen(service))) { | |
181 | int len = strlen(host)+strlen(proto)+strlen(port)+5; | |
182 | ||
183 | if (!(url = malloc(len))) { | |
184 | perror("malloc"); | |
185 | return NULL; | |
186 | } | |
187 | ||
188 | snprintf(url, len, "%s://%s:%s", proto, host, port); | |
189 | url[len-1] = 0; | |
190 | break; | |
191 | } | |
192 | } | |
193 | ||
194 | } while(curr.tv_sec < start.tv_sec+SAP_TIMEOUT); | |
195 | ||
196 | mreq.imr_multiaddr.s_addr = inet_addr(SAP_ADDR); | |
197 | mreq.imr_interface.s_addr = INADDR_ANY; | |
198 | setsockopt (fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); | |
199 | ||
200 | return url; | |
201 | } |